http://www.adobe.com/support/techdocs/342e.htm , read it, may come to some use
this doesnt mention .tga, and i think it handles the alpha differently…and you have to use 32 bit when u save the texture i’m told…this is not mentioned.
i don’t know what the heck alpha channels are…but please tell me if this is what you guys are looking for: http://mysite.iptic.com/gargola/fence.zip
An alpha channel is a transparent channel.
Just start out with a transparent backround when you want to make an alpha texture, a tga does have to be 32 bit to keep the alpha channel.
it’s really simple:
first you have a picture lets say of a tree, nice brown trunk, green leaves etc… these are the rgb channels of the image…
in photoshop there is a channels window, here you can add a new channel (an alpha) alpha channels are read in greyscale, so white stuff will be totally visible and black stuff totally transparent.
taking that to the image of the tree we would use the silhuet of the tree, and make that a white image on the alpha channel and leave the rest black…this way an alpha-face will show the brown truck and the green leaves and leave the rest transparent.
Take a look at this file http://www2.hku.nl/~carl/Downloads/tree.zip and the files in it to see more…
You can also animate alpha values, and color values…